The ultimate surprise for the city's 300 children with heart disease this year was a greeting card from Father Christmas delivered by Hongkong Post. In the card, Santa Claus said: 'It snows heavily at the North Pole, yet I've prepared plenty of gifts for everyone. Do not make your parents angry. Let's have a joyful festival.' He signed the letter in English and Chinese. The idea came from Hongkong Post, which joined the Children's Heart Foundation - an Operation Santa Claus beneficiary - to send an 'additional surprise' to the children, aged between three and eight, who suffer from congenital heart disease. 'We hope the children will feel this Christmas is a little bit special with our little effort,' Mary Chung Shuk-kuen, a Hongkong Post spokeswoman, said. This year, 3,000 lucky children received Christmas cards, and Postmaster General Tam Wing-pong also took 50 letters from the children to Santa on a duty visit to Finland.